H3C Technologies H3C SR8800 - Manual (Page 179)

163
To enable LSP flash flooding:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter IS-IS view. isis [ process-id ] [ vpn-instance vpn-instance-name ] N/A
3. Enable LSP flash
flooding.
flash-flood [ flood-count flooding-count |
max-timer-interval flooding-interval | [ level-1 |
level-2 ] ] *
Not enabled by
default
Enabling LSP fragment extension
To enable LSP fragment extension:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter IS-IS view.
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
N/A
3. Enable LSP fragment
extension and specify the
working mode.
lsp-fragments-extend [ [ level-1 | level-1-2 |
level-2 ] | [ mode-1 | mode-2 ] ] *
Not enabled by default
4. Configure a virtual system
ID.
virtual-system virtual-system-id Not configured by default
NOTE:
•
After LSP fragment extension is enabled for an IS-IS process, the MTUs of all the interfaces running the
IS-IS process must not be less than 512; otherwise, LSP fragment extension will not take effect.
• At least one virtual system needs to be configured for the router to generate extended LSP fragments. An
IS-IS process allows 50 virtual systems at most.
Limiting LSP flooding
In well-connected NBMA networks, many P2P links exist. Figure 62 shows a fully meshed network, where
Routers A, B, C and D run IS-IS. When Router A generates an LSP, it floods the LSP out GigabitEthernet
1/1/1, GigabitEthernet 1/1/2 and GigabitEthernet 1/1/3. After receiving the LSP from
GigabitEthernet 1/1/3, Router D floods it out GigabitEthernet 1/1/1 and GigabitEthernet 1/1/2 to
Router B and Router C. However, Router B and Router C have already received the LSP from Router A. LSP
flooding consumes extra bandwidth.